package com.smartstate.gateway.filter;

import com.fasterxml.jackson.databind.ObjectMapper;
import io.netty.buffer.ByteBufAllocator;
import lombok.SneakyThrows;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.util.MultiValueMap;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import javax.annotation.Resource;
import java.net.URI;
import java.nio.charset.StandardCharsets;

/**
 * 请求日志过滤器
 *
 * @author 2020/11/10
 */
//@Component
@Slf4j
public class RequestLogFilter implements GlobalFilter, Ordered {
    @Resource
    ObjectMapper objectMapper;
    @SneakyThrows
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest serverHttpRequest = exchange.getRequest();
        String method = serverHttpRequest.getMethodValue();
        if ("POST".equals(method)) {
            return DataBufferUtils.join(exchange.getRequest().getBody())
                    .flatMap(dataBuffer -> {
                        byte[] bytes = new byte[dataBuffer.readableByteCount()];
                        dataBuffer.read(bytes);
                        String bodyStr = new String(bytes, StandardCharsets.UTF_8);
                        log.info("------------------------------- POST请求参数 ------------------------------------");
                        log.info(bodyStr);
                        //TODO 拿到POST日志后的操作
                        //下面的将请求体再次封装写回到request里，传到下一级，否则，由于请求体已被消费，后续的服务将取不到值
                        URI uri = serverHttpRequest.getURI();
                        ServerHttpRequest request = serverHttpRequest.mutate().uri(uri).build();
                        DataBuffer bodyDataBuffer = this.stringBuffer(bodyStr);
                        Flux<DataBuffer> bodyFlux = Flux.just(bodyDataBuffer);

                        request = new ServerHttpRequestDecorator(request) {
                            @Override
                            public Flux<DataBuffer> getBody() {
                                return bodyFlux;
                            }
                        };
                        //封装request，传给下一级
                        return chain.filter(exchange.mutate().request(request).build());
                    });
        } else if ("GET".equals(method)) {
            MultiValueMap<String, String> queryParams = serverHttpRequest.getQueryParams();
            log.info("------------------------------- GET请求参数 ------------------------------------");
            log.info(objectMapper.writeValueAsString(queryParams));
            return chain.filter(exchange);
        }
        return chain.filter(exchange);
    }

    private DataBuffer stringBuffer(String value) {
        byte[] bytes = value.getBytes(StandardCharsets.UTF_8);

        NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(ByteBufAllocator.DEFAULT);
        DataBuffer buffer = nettyDataBufferFactory.allocateBuffer(bytes.length);
        buffer.write(bytes);
        return buffer;
    }

    @Override
    public int getOrder() {
        return 0;
    }
}
